Internal gear pumps are known. They have a pinion, i.e. an externally toothed gearwheel, which is arranged eccentrically in an internally toothed ring gear and meshes with the ring gear at one point on the circumference or in a segment of the circumference. The pinion and the ring gear can also be considered as gearwheels of the internal gear pump. Through rotary driving of one of the two gearwheels, generally the pinion, the other gearwheel, that is to say generally the ring gear, is also driven in rotation, and the internal gear pump delivers fluid in a manner known per se, delivering brake fluid in a hydraulic vehicle braking system.
Opposite the segment of the circumference in which the pinion meshes with the ring gear, the internal gear pump has a crescent-shaped free space between the pinion and the ring gear, which is here referred to as the pump space. Arranged in the pump space is a separating piece, which divides the pump space into a suction space and a pressure space. Owing to its typical shape, the separating piece is also referred to as a crescent or crescent piece, while another name is filler piece. An inner side of the separating piece, said inner side typically being of a hollow round shape, rests on tooth tips of teeth of the pinion, and an outer side of the separating piece, said outer side typically being curved outward, rests on tooth tips of teeth of the ring gear, with the result that the separating piece encloses fluid volumes in tooth interspaces between the teeth of the gearwheels of the internal gear pump. When driven in rotation, the gearwheels deliver the fluid in the tooth interspaces from the suction side to the pressure side.
German Laid-Open Application DE 10 2009 047 643 A1 discloses an internal gear pump of this kind, the separating piece of which is of multipart construction and has an inner part, the inner side of which rests on the tooth tips of the teeth of the pinion, and an outer part, the outer side of which rests on the tooth tips of teeth of the ring gear.